diff --git a/impresso/models/userBitmap.py b/impresso/models/userBitmap.py
index 17974ee..521a3b4 100644
--- a/impresso/models/userBitmap.py
+++ b/impresso/models/userBitmap.py
@@ -66,6 +66,12 @@ def get_up_to_date_bitmap(self) -> bytes:
         return int_to_bytes(value)
 
     def get_bitmap_as_int(self):
+        """
+        Converts the bitmap from bytes to an integer.
+
+        Returns:
+            int: The bitmap as an integer.
+        """
         return int.from_bytes(self.bitmap, byteorder="big")
 
     def get_bitmap_as_key_str(self):
diff --git a/impresso/tasks.py b/impresso/tasks.py
index 57262ce..ea35ad2 100644
--- a/impresso/tasks.py
+++ b/impresso/tasks.py
@@ -112,7 +112,7 @@ def export_query_as_csv_progress(
     job_id: int,
     query: str,
     search_query_id: int,
-    user_bitmap_key: str,
+    user_bitmap_key: int,
     query_hash: str = "",
     progress: float = 0.0,
     skip: int = 0,
@@ -130,7 +130,7 @@ def export_query_as_csv_progress(
         job_id (int): The ID of the job to update.
         query (str): The query string to execute.
         search_query_id (int): The ID of the search query.
-        user_bitmap_key (str): The user bitmap key.
+        user_bitmap_key (int): The user bitmap key, as int.
         query_hash (str, optional): The hash of the query. Defaults to an empty string.
         skip (int, optional): The number of records to skip. Defaults to 0.
         limit (int, optional): The maximum number of records to retrieve per page. Defaults to 100.
@@ -199,20 +199,16 @@ def export_query_as_csv(
         description=description,
         extra={"query": query, "query_hash": query_hash},
     )
+    attachment = Attachment.create_from_job(job, extension="csv")
     # if decri
     # get user bitmap, if any
-    try:
-        user = User.objects.get(pk=user_id)
-        user_bitmap_key = user.bitmap.get_bitmap_as_key_str()
-    except User.bitmap.RelatedObjectDoesNotExist:
-        logger.info(f"[job:{job.pk} user:{user_id}] no bitmap found for user!")
-        user_bitmap_key = bin(UserBitmap.USER_PLAN_GUEST)[:2]
-
+    user_bitmap, created = UserBitmap.objects.get_or_create(user_id=user_id)
     logger.info(
         f"[job:{job.pk} user:{user_id}] launched! "
-        f"query:{query_hash} bitmap:{user_bitmap_key} description:{description}"
+        f"- Using bitmap {user_bitmap.get_bitmap_as_int()} (created:{created}) "
+        f"- attachment:{attachment.pk}"
     )
-    attachment = Attachment.create_from_job(job, extension="csv")
+
     update_job_progress(
         task=self,
         job=job,
@@ -226,7 +222,7 @@ def export_query_as_csv(
         query=query,
         query_hash=query_hash,
         search_query_id=search_query_id,
-        user_bitmap_key=user_bitmap_key,
+        user_bitmap_key=user_bitmap.get_bitmap_as_int(),
     )
 
 
@@ -238,12 +234,22 @@ def export_collection_as_csv(
     query: str,
     query_hash: str = "",
 ) -> None:
-    try:
-        user = User.objects.get(pk=user_id)
-        user_bitmap_key = user.bitmap.get_bitmap_as_key_str()
-    except User.bitmap.RelatedObjectDoesNotExist:
-        logger.warning(f"[job:{job.pk} user:{user_id}] no bitmap found for user!")
-        user_bitmap_key = bin(UserBitmap.USER_PLAN_GUEST)[:2]
+    """
+    Initiates a job to export a collection as a CSV file and starts the export_query_as_csv_progress task
+    like export_query_as_csv.
+
+    Args:
+        self: The instance of the class.
+        user_id (int): The ID of the user initiating the export.
+        collection_id (int): The ID of the collection to be exported.
+        query (str): The query string to be exported.
+        query_hash (str, optional): A hash of the query string. Defaults to an empty string.
+
+    Returns:
+        None
+
+    """
+    user_bitmap, created = UserBitmap.objects.get_or_create(user_id=user_id)
     try:
         collection = Collection.objects.get(pk=collection_id, creator__id=user_id)
     except Collection.DoesNotExist:
@@ -260,12 +266,15 @@ def export_collection_as_csv(
             "query_hash": query_hash,
         },
     )
+    # create empty attachment and attach automatically to the job
+    attachment = Attachment.create_from_job(job, extension="csv")
     logger.info(
         f"[job:{job.pk} user:{user_id}] launched! "
-        f"query:{query_hash} bitmap:{user_bitmap_key} description:{job.description}"
+        f"- Using bitmap {user_bitmap.get_bitmap_as_int()} (created:{created}) "
+        f"- attachment:{attachment.pk} "
+        f"- query:{query_hash} description:{job.description}"
     )
-    # create empty attachment and attach automatically to the job
-    Attachment.create_from_job(job, extension="csv")
+
     # add query to extra. Job status should be INIT
     update_job_progress(
         task=self,
@@ -279,7 +288,7 @@ def export_collection_as_csv(
         job_id=job.pk,
         query=query,
         query_hash=query_hash,
-        user_bitmap_key=user_bitmap_key,
+        user_bitmap_key=user_bitmap.get_bitmap_as_int(),
     )
 
 
diff --git a/impresso/tests/test_solr.py b/impresso/tests/test_solr.py
index ade23c1..f6236a4 100644
--- a/impresso/tests/test_solr.py
+++ b/impresso/tests/test_solr.py
@@ -1,6 +1,7 @@
 import unittest
 from impresso.utils.solr import serialize_solr_doc_content_item_to_plain_dict
 from impresso.utils.solr import mapper_doc_redact_contents
+from impresso.utils.bitmask import BitMask64
 
 
 class SolrTestCase(unittest.TestCase):
@@ -49,7 +50,7 @@ def test_mapper_doc_redact_contents(self):
         result_redacted = mapper_doc_redact_contents(
             doc={**doc},
             # not working user bitmask key
-            user_bitmap_key="0000",
+            user_bitmask=BitMask64("0000"),
         )
         self.assertEqual(result_redacted.get("content"), "[redacted]")
         self.assertEqual(result_redacted.get("title"), doc.get("title"))
@@ -57,7 +58,7 @@ def test_mapper_doc_redact_contents(self):
         result_ok = mapper_doc_redact_contents(
             doc={**doc},
             # working user bitmask key
-            user_bitmap_key="1100",  # 0b10110101
+            user_bitmask=BitMask64("1100"),  # 0b10110101
         )
         self.assertEqual(
             result_ok.get("content"),
diff --git a/impresso/utils/solr.py b/impresso/utils/solr.py
index e4ea7f2..f189c7b 100644
--- a/impresso/utils/solr.py
+++ b/impresso/utils/solr.py
@@ -31,7 +31,7 @@ def serialize_solr_doc_content_item_to_plain_dict(
     return result
 
 
-def mapper_doc_redact_contents(doc: dict, user_bitmap_key: str) -> dict:
+def mapper_doc_redact_contents(doc: dict, user_bitmask: BitMask64) -> dict:
     """
     Redacts the content of a document based on its bitmap key (_bm_get_tr_s)
     or its availability and year.
@@ -43,7 +43,7 @@ def mapper_doc_redact_contents(doc: dict, user_bitmap_key: str) -> dict:
     Args:
         doc (dict): A dictionary representing the document obtained via the serializer function .
             to be considered valid, tt must contain the key "year".
-        user_bitmap_key (str): The user's bitmap key, as string.
+        user_bitmask (BitMask64): The user's bitmap key, as BitMask64 instance.
 
     Returns:
         dict: The modified document dictionary with redacted content if applicable.
@@ -62,12 +62,12 @@ def mapper_doc_redact_contents(doc: dict, user_bitmap_key: str) -> dict:
 
     if doc.get("_bm_get_tr_i", None) is not None:
         is_transcript_available = is_access_allowed(
-            accessor=BitMask64(user_bitmap_key),
+            accessor=user_bitmask,
             content=BitMask64(doc["_bm_get_tr_i"], reverse=True),
         )
     elif doc.get("_bm_get_tr_s", None) is not None:
         is_transcript_available = is_access_allowed(
-            accessor=BitMask64(user_bitmap_key),
+            accessor=user_bitmask,
             # nop need to reverse if this is a string
             content=BitMask64(doc["_bm_get_tr_s"]),
         )
diff --git a/impresso/utils/tasks/export.py b/impresso/utils/tasks/export.py
index 00ce0be..30dfc76 100644
--- a/impresso/utils/tasks/export.py
+++ b/impresso/utils/tasks/export.py
@@ -8,6 +8,7 @@
 from ...models import Job
 from ...solr import find_all
 from ...utils.tasks import get_pagination
+from ...utils.bitmask import BitMask64
 from ...utils.solr import (
     mapper_doc_remove_private_collections,
     mapper_doc_redact_contents,
@@ -44,7 +45,7 @@ def helper_export_query_as_csv_progress(
     job: Job,
     query: str,
     query_hash: str,
-    user_bitmap_key: str,
+    user_bitmap_key: int,
     ignore_fields: list = [],
     skip: int = 0,
     limit: int = 100,
@@ -59,6 +60,8 @@ def helper_export_query_as_csv_progress(
     Args:
       job (Job): The job object containing user profile information.
       query (str): The SOLR query string.
+      query_hash (str): The hash of the query string.
+      user_bitmap_key (int): The user's bitmap key.
       skip (int, optional): The number of items to skip. Defaults to 0.
       limit (int, optional): The maximum number of items per page. Defaults to 0.
       logger (Any, optional): The logger object. Defaults to None.
@@ -93,7 +96,7 @@ def helper_export_query_as_csv_progress(
             loops,
             progress,
         )
-
+    user_bitmask = BitMask64(user_bitmap_key)
     logger.info(
         f"[job:{job.pk} user:{job.creator.pk}] Opening file in APPEND mode:"
         f"{job.attachment.upload.path}"
@@ -158,7 +161,7 @@ def helper_export_query_as_csv_progress(
             )
             content_item = mapper_doc_redact_contents(
                 doc=content_item,
-                user_bitmap_key=user_bitmap_key,
+                user_bitmask=user_bitmask,
             )
             # removed unwanted fields from the content_item
             content_item = {k: v for k, v in content_item.items() if k in fieldnames}